Observation of spatial charge and spin correlations in the 2D Fermi-Hubbard model
Author(s)Khatami, E.; Trivedi, N.; Paiva, T.; Rigol, M.; Cheuk, Lawrence W.; Nichols, Matthew Alan; Lawrence, Katherine R; Okan, Melih; Zhang, Hao; Zwierlein, Martin; ... Show more Show less
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Strong electron correlations lie at the origin of high-temperature superconductivity. Its essence is believed to be captured by the Fermi-Hubbard model of repulsively interacting fermions on a lattice. Here we report on the site-resolved observation of charge and spin correlations in the two-dimensional (2D) Fermi-Hubbard model realized with ultracold atoms. Antiferromagnetic spin correlations are maximal at half-filling and weaken monotonically upon doping. At large doping, nearest-neighbor correlations between singly charged sites are negative, revealing the formation of a correlation hole, the suppressed probability of finding two fermions near each other. As the doping is reduced, the correlations become positive, signaling strong bunching of doublons and holes, in agreement with numerical calculations. The dynamics of the doublon-hole correlations should play an important role for transport in the Fermi-Hubbard model.
DepartmentHarvard-MIT Center for Ultracold Atoms; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Research Laboratory of Electronics
American Association for the Advancement of Science (AAAS)
Cheuk, L. W.; Nichols, M. A.; Lawrence, K. R.; Okan, M.; Zhang, H.; Khatami, E.; Trivedi, N.; Paiva, T.; Rigol, M. and Zwierlein, M. W. “Observation of Spatial Charge and Spin Correlations in the 2D Fermi-Hubbard Model.” Science 353, no. 6305 (September 15, 2016): 1260–1264. © 2016 American Association for the Advancement of Science (AAAS)